2004 gs500f backfiring / fuel problem

[median17]

Hi all,

Here is my problem.  I have a 2004 gs500f...when I get her started up during the warm up period if i rev the engine to ~1500 - 2000 rpm i get a pop coming out of the carbs and into the air box.  Not only that, but it seems like my carbs are leaking gas even when the bike is off (and petcock not on PRI).  I have checked the petcock and it is in working order, replaced the spark plugs, and just today I have taken the carbs out again and adjusted the floats so the valve closes earlier.  I have taken the carbs out before and cleaned them multiple times, all of which I have checked the float height and it has been dead on spec every time as well as make sure the needle valve is actually closing fully.  Also, after a day or so of not riding the bike, when I try to start it up it requires me to give it some throttle and crank it for maybe 10ish seconds before it will start.

Over the winter I have done the following work to the bike:

1. replaced the started clutch
2. removed and cleaned carbs multiple times
3. replaced distributor bolt
4. recently replaced spark plugs

After I did all of these things i got the bike running (cuz it wasn't before) but now I am running into the current backfiring / fuel problem and i'm not sure what to look at next.  All i can think of is timing.  Is there an advance on the distributor that could be out of whack?

[Big Rich]

No, your timing isn't readily adjustable. MAYBE a quarter of a degree or something, but I wouldn't worry about it.

What condition is your battery in? Can't be too bad if the starter spins the motor for 10ish seconds. And how much fuel is actually leaking from the carbs (and where from exactly)? The backfiring into the carbs is usually a sign of a lean condition but your timing on the chain could be off drastically. And when it pops back into the carbs it usually spits gas out onto the filter.